Hydrogen is a very energetic, clean burning fuel. It can be burned with great energy release in air or oxygen-enriched atmosphere to yield water without unburned hydrocarbons or carbon oxides as byproducts. The problem, of course, is that it is difficult to store hydrogen for mobile applications such as automobiles or trucks. Hydrogen can be stored as a liquid only if it can be kept very cold and under high pressure. If hydrogen is to be stored as a gas, most previous approaches have been to use metal containers suitable for confining the gas under very high pressures. There are no practical materials that can reversibly absorb or adsorb appreciable amounts of hydrogen at low pressure and give it up as a gas on demand. Accordingly, hydrogen has not been available as a practical fuel in vehicular applications.
There is a need to advance the art of hydrogen storage materials that can take up and temporarily hold substantial quantities of hydrogen at relatively low pressure and give up gaseous hydrogen on demand.